Question

Write an equation for the line that passes through the points (-1,-12) and (4,8)​

Answer 1

Answer:

y = 4x - 8

Step-by-step explanation:

(-1, -12) & (4, 8)

First you want to find the slope of the line that passes through these points. To find the slope of the line, we use the slope formula: (y₂ - y₁) / (x₂ - x₁)

Plug in these values:

(8 - (-12)) / (4 - (-1))

Simplify the parentheses.

= (8 + 12) / (4 + 1)

= (20) / (5)

Simplify the fraction.

20/5

= 4

This is your slope. Plug this value into the standard slope-intercept equation of y = mx + b.

y = 4x + b

To find b, we want to plug in a value that we know is on this line: in this case, I will use the second point (4, 8). Plug in the x and y values into the x and y of the standard equation.

8 = 4(4) + b

To find b, multiply the slope and the input of x(4)

8 = 16 + b

Now, subtract 16 from both sides to isolate b.

-8 = b

Plug this into your standard equation.

y = 4x - 8

This is your equation.

Check this by plugging in the other point you have not checked yet (-1, -12).

y = 4x - 8

-12 = 4(-1) - 8

-12 = -4 - 8

- 12 = -12

Your equation is correct.

Hope this helps!